XBMC, the very popular open-source media center software, has been successfully ported to Android. The folks at XBMC tell us this on their blog -
Today we announce XBMC for Android. Not a remote, not a thin client; the real deal. No root or jailbreak required. XBMC can be launched as an application on your set-top-box, tablet, phone, or wherever else Android may be found.
If you don't understand just what this is, think of having Windows Media Center running on your Android device, fully customizable, open-source, and with full Python plug-in support. Now think of it on Google TV boxes, Android-on-a-stick style devices, or the Nexus Q. Music, video, internet apps like Pandora, all running on Android device. XBMC does all this, and more. Have a look at Wikipedia if you're not familiar with the media center concept.
For now, no public builds are available. There's still some things to iron out, and the folks at XBMC only want folks who can actively help fix the bugs using it. They've released the source code to make this happen, and you can find it (and more info) at the link below.